Spin precession and modulation in ballistic cylindrical nanowires due to the Rashba effect

TL;DR

This paper theoretically investigates spin precession and modulation in ballistic cylindrical InAs nanowires caused by Rashba spin-orbit coupling, revealing how spin states evolve and can be controlled via magnetic fields.

Contribution

It provides a detailed theoretical analysis of spin dynamics in cylindrical nanowires with Rashba coupling, including eigenstates and dispersion relations, highlighting mechanisms for spin precession and modulation.

Findings

Periodic modulation of axial spin component along the wire

Existence of a superposition state with opposite spin precession at zero magnetic field

Additional spin precession component induced by axial magnetic field

Abstract

The spin precession in a cylindrical semiconductor nanowire due to Rashba spin-orbit coupling has been investigated theoretically using an InAs nanowire containing a surface two-dimensional electron gas as a model. The eigenstates, energy-momentum dispersion, and the energy-magnetic field dispersion relation are determined by solving the Schr\"odinger equation in a cylindrical symmetry The combination of states with the same total angular momentum but opposite spin orientation results in a periodic modulation of the axial spin component along the axis of the wire. Spin-precession about the wires axis is achieved by interference of two states with different total angular momentum. Because a superposition state with exact opposite spin precession exists at zero magnetic field, an oscillation of the spin orientation can be obtained. If an axially oriented magnetic field is applied, the spin gains an additional precessing component.